D3251: Management of Caribbean fruit fly, Anastrepha suspensa, using plant essential oils

The Caribbean fruit fly, Anastrepha suspensa, is a major pest to over 100 host species in Florida, the Caribbean islands and countries in Central America. Currently, the management of this pest relied on conventional insecticidal bait sprays in commercial groves. However, extensive insecticide applications can lead to development of insecticide resistance. The resistance level of A. suspensa in South Florida has been monitored since 2022, and the resistance ratio has so far been < 10 for carbamates (i.e. methomyl), indicating development of mild resistance level in field collected flies. To manage further development of resistance, research has focused on plant extracted essential oils (EO) with demonstrated insecticidal effects as a safer alternative to conventional synthetic insecticides. We evaluated a series of EOs extracted from Cupressaceae, Zygophyllaceae, Myrtaceae, Lamiaceae, Asteraceae, and Apiaceae and chemically synthesized pthalimide derivatives, which are environmental degradable, to determine the contact toxicity against female A. suspensa under laboratory conditions. The results showed that six EOs and three pthalimide derivatives were effective against A. suspensa, with varied LD50 levels. Results also showed that anisole (EO extracted from Apiaceae) was not only effective via contact, but also showed strong fumigation and residue effects. Our study showed that the tested EOs and pthalimide derivatives have potential to be used as environmentally-friendly alternatives to conventional insecticides for management of Caribbean fruit fly.